1. Field of the Invention
This invention relates to medical instruments and, more particularly, to a medical instrument for repositioning and cutting a human body tissue at an operating site. The invention is also directed to a method of using such a medical instrument.
2. Background Art
In many surgical procedures, tissue is required to be controllably dissected. This dissection is commonly effected using cauterization. Oftentimes, the dissection is effected using only a blade with a sharp cutting edge that is drawn against the region of the tissue to be cut.
While it is known to manipulate tissue through an instrument having a hooked distal end at which a cutting blade is located, heretofore there have been a number of limitations associated with this basic instrument configuration.
As one example, U.S. Pat. No. 5,397,333 (Knoepfler) discloses an instrument wherein a sharp cutting blade is defined in a cutting space within the curvature of a hooked end. During introduction into, and movement of the hooked end within a cavity, tissue may be inadvertently brought into contact with the exposed cutting blade. This can lead to collateral damage around the intended site and may lengthen procedure times and potentially necessitate internal treatment of tissue to repair inadvertently cut regions thereof.
While use of a cannula may shield tissue from the cutting blade as the instrument is initially directed towards an operating site, the potential for collateral damage arises again, after the cannula is removed, as a surgeon relocates the hooked end to different sites as a procedure may demand. Further, damage may be inflicted at the conclusion of a procedure as the instrument, with the exposed cutting blade, is withdrawn.
Additionally, once the desired tissue portion is strategically situated in the cutting space preparatory to effecting a cut, the tissue has a tendency to escape from the cutting space. That is, the guiding inside surface of the hooked region, which is generally smooth, allows free sliding of the tissue therealong which could precipitate separation of the targeted tissue from the instrument. This may necessitate repeating steps, which adds undesirably to the overall time necessary to perform the procedure.
Further, uncontrolled tissue movement relative to the hooked end may make it difficult, or impossible, to precisely locate a cut.
The industry continues to seek better designs for instruments of this type, focused on at least the aforementioned limitations of existing designs.